The aim of this chapter is first to broadly situate the modern dialects of northern England in their historical context by reviewing a selection of the key phonological features which have historically distinguished the North from the rest of the country; having laid this groundwork, I will then explore a case study which demonstrates the relevance of the modern northern dialects to the study of historical linguistic processes. Data from Kolb&#8217;s <i>Linguistic atlas of England: Phonological atlas of the Northern region</i> is used to map the northern dialect outcomes of the English Great Vowel Shift, which reveals regular geographic patterns that aid our understanding of the structure and chronology of the shift.